1. Field of the Invention
The present invention relates in general storage systems, and particularly to, systems and methods for detecting supported small form-factor pluggable (SFP) devices.
2. Description of the Related Art
In, for example, a Fibre Channel storage device, there is a host adapter card that handles all Fibre Channel protocol interactions. It is common practice to have a small form-factor pluggable (SFP) device that can be hot-plugged into a port of the host adapter card. The SFP device interfaces the host adapter firmware with a Fibre Channel cable.
Each SFP device typically includes one of two different types of optical lasers, a long-wave SFP laser or a short-wave SFP laser. Long-wave lasers support distances in the kilometer range while short-wave lasers support distances in the hundreds of meters range. The host adapter card is also frequently designed to support either a long-wave SFP laser or a short-wave SFP laser.
With the ability to interchange and hot-plug SFP devices into a host adapter card, several issues have been noticed. The first issue involves using unsupported SFP devices. There are many different vendors that manufacture SFP devices. In theory, all SFP devices should all operate in an identical manner, but this is not always the case. Since SFP devices are “hot-pluggable,” an unsupported SFP device may be plugged into the host adapter card, which typically affects the performance of the host adapter card.
The second issue involves compatibility between a host adapter card and a SFP device. Specifically, it is a mistake to combine a long-wave laser SFP device with a short-wave laser host adapter card or vice versa. Because the physical connections of short-wave laser devices and long-wave laser devices are identical, it is possible to connect incompatible host adapter cards and SFP devices.
Using an unsupported SFP device or mixed wave types can lead to unpredictable results, which are frequently hard to diagnose without physical inspection and/or additional instrumentation. One potential negative impact is corrupted data being received or sent by the SFP device, which requires frequent data re-driving and congestion. Another potential negative impact is the failure to bring the Fibre Channel link up, which would render the link useless since access to the machine would be prevented.
One known solution is to physically label the SFP device and the host adapter card. This label could include a serial number or part number, which would have to be cross referenced to determine the SFP manufacturer and/or wave type. The label might also directly include the manufacturer name and/or wave type. The drawback of this solution is that it requires a user to physically look at the two devices and the labels have the potential of being removed, intentionally or inadvertently. Also, once the host adapter card is installed into a machine, it might not be possible to visually inspect the label of the SFP device. Furthermore, there is also the possibility that a batch of SFP devices is mislabeled or that a hostile user will knowingly install an unsupported SFP and, as a result, potentially cause harmful side affects in the computing environment.